Free NCMA Basic Laboratory Procedures and Specimen Handling Questions and Answers

Question 1

When performing a venipuncture, which color-topped tube should be drawn first if blood cultures are not ordered?

Accepted Answer

Light Blue

Answer

Following the standard order of draw to prevent cross-contamination of additives, the light blue top tube is drawn first after blood cultures. This tube contains sodium citrate and is used for coagulation studies, which are sensitive to other additives.

Question 2

What is the additive in a lavender-topped tube and what is its purpose?

Accepted Answer

EDTA, to prevent clotting by binding calcium

Answer

The lavender (or purple) top tube contains the anticoagulant ethylenediaminetetraacetic acid (EDTA). EDTA works by binding to calcium in the blood, which prevents clotting and preserves the shape and structure of blood cells for hematology tests like a CBC.

Question 3

A medical assistant is instructing a patient on how to collect a clean-catch midstream urine specimen. Which instruction is correct?

Accepted Answer

Wipe the area, begin to urinate in the toilet, then collect the sample.

Answer

A clean-catch midstream specimen requires careful cleansing of the genital area to prevent contamination. The patient should begin urinating into the toilet, then move the collection cup into the stream to collect the sample, and finally finish urinating in the toilet.

Question 4

When is the most appropriate time to label a patient's specimen container?

Accepted Answer

Immediately after collection, in front of the patient.

Answer

To prevent errors, specimen containers must be labeled immediately after collection, in the presence of the patient. Pre-labeling containers or labeling them after leaving the room increases the risk of misidentification and medical errors.

Question 5

What is the purpose of inverting a blood collection tube after it is filled?

Accepted Answer

To ensure proper mixing of the additive and the blood.

Answer

Tubes with additives, such as anticoagulants or clot activators, must be gently inverted a specific number of times. This action ensures that the additive is thoroughly mixed with the blood specimen to function correctly, either by preventing clotting or promoting it.

NCMA - National Certified Medical Assistant Practice Test

NCMA - National Certified Medical Assistant Practice Test

Free NCMA Basic Laboratory Procedures and Specimen Handling Questions and Answers